Air feeding furnace front structure



Nov. 25, 1947. G. A; REHM AIR FEEDING FURNACE FRONT STRUTURE Filed A 2,1944 GUSTAV A. REHM Patented Nov. 25, 1947 UNITED STATES PATENT OFFICEAIR' FEEDING' FURNACE FRONT STRUCTURE Gustav A. Rehm, Worcester, Mass.,assignor to Riley Stoker Corporation, Worcester, Mass., a corporation ofMassachusetts Application August 2,1944, Serial No. 547,'705

6 Clams. 1

This invention relates to furnaces, and more particularly to theConstruction of furnaces of the type having an upright wall providedwith openings through which fuel is introduced for combustion within thefurnace.

In one commonly used furnace Construction, the front wall of the furnaceis provided with a plurality of horizontally spaced openings throughwhich fuel is projected rearwardly by mechanical feeders knows as"spreader stokers. The fine particles of fuel burn in suspension, whilethe coarse particles fall upon a grate. Upright piers of refractorymaterial serve to separate the openings. These piers are exposed toradiant heat from both sides as well as from the rear, and their usefullife under these Operating conditions is very short. Further dificultiesare encountered through failure of the fine particles to ignitepromptly, many such particles being carried out of the combustionchamber in an unburned condition by the action of the furnace gases.

It is accordingly one object of the invention to provide a furnaceConstruction which will Withstand severe Operating conditions throughouta long life of useful service.

It is a further object of the invention to provide a new andadvantageous Construction for the refractory piers between the fuelinlet openings of a furnace, whereby the life of such piers will begreatly prolonged.

It is a further object of the invention to provide an improvedConstruction of furnace for use with spreader stokers, whereby a moreefiicient combustion of the fuel may be obtained.

With these and other objects in view, as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

Referring to the drawings illustrating one embodiment of the invention,and in which like reference numerals indicate like parts,

Fig. 1 is a horizontal section through the front portion of a furnace,the section being taken on the line l of Fig. 2;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a perspective View of a refractory block; and

Fig. 5 is a fragmentary View of a slightly modified Construction.

The embodiment illustrated comprises a furnace having two upright sidewalls ID, a front wall Il, a grate !2, and a dead plate I i in front ofthe grate. The front wall ll is of the wellknown structurally supportedtype, and its lower edge ,is spaced above the level of the grate anddead plate. This space between the dead plate !4 and the lower edge ofthe wall ll thereabove is divided into a plurality of openings !5 bymeans of upright refractory piers !6. An upright vertical metal frontplate [8 is mounted at the front of the furnace and forms a support forspreader sto-ker mechanisms |9 which serve to project fuel rearwardlythrough the openings !5. These mechanisms !9 are of any suitable andwell-known Construction, and as shown each mechanism comprises a, hopper2! from which fuel descends by gravity to a reciprocable ram 22, thisram feeding the fuel at a controlled rate to a rotating reel 23 whichprojects the fuel rearwardly. The front plate s is provided with doors25 located directly beneath the stok-er mechanisms !9 to afford accessto the fuel bed, and With doors 26 which afford access to the ash pit orair chamber 2'! beneath the grate |2.

The piers !6 are of hollow Construction, and provision is made forcirculating air through the interier of the piers and then dischargingthis air into the furnace to aid ethe combustion of the fuel. Preferablyeach pier includes a series of superimposed refractory blocks 29, withthe lowermost block supported on the dead plate Il. Each block 29 isV-shaped or bifurcated in plan, and the two branches of the V extendtoward the front and into contact with the front plate !8 to provide avertical passage for the flow of air. This passage is closed at the topby a special block 30 of the same external shape as the blocks 29 butwithout an internal opening. The space between the top block 30 and thelower edge of the front wall ll is filled with plastic refractorymaterial 3l. A vertical flanged metal bar 33 of I cross section islocated within each pier 16 and suitably fastened to the front plate,and each block 29 is provided with a pair of opposed inwardly extendinglugs 34 which engage the fianges of the bar to anchor the blocks inplace. Each block 29 is also provided on both its upper and its lowersurfaces with a pair of grooves 35 which diverge in a rearwarddirection, these grooves forming channels for the flow of air from theinterior of the piers to the furnace.

A'r is supplied to the interiors of the piers !G either by forced draftor by natural draft. In the event the furnace is operated with forceddraft, the air chamber 21 will be supplied with air under pressure froma suitable fan, and some of this air may be admitted to the lower endsof the piers IS through pipes 31 leading through the dead plate I 4 andprovided with valves 38. As shown on F'g. l, two of these pipes may beprovided for each pier, on opposite sides of the anchor bar 33. In theevent the furnace is operated with natural draft, small doors 40 may beprovided in the front plate !8 to admit air to the intero' of each pier16 on opposite sides of the anchor bar 33.

In Fig, 5 a slightly modified Construction is shown, each of therefractory blocks in the pier !6 being formed of three interfttingpieces, namely a rear nose piece 42 and two wing pieces 43. Verticalribs 45 may be provided on the front plate [8 to aid in retaining thewing pieces 43. The lugs 34 and air channels 35 are formed on the nosepiece 42.

The operation of the invention will now be apparent from the abovedisclosure. The hoppers 2l are filled with fuel, which preferably hasbeen crushed, and the rams 22 feed the fuel at a controlled rate to therotating reels 23, which project the fuel rearwardly through theopenings I5. The fine particles of fuel burn in suspension, while thelarger particles are deposited on the grate l2 and form a bed of burningfuel. Air enters the piers IS, either by natural draft through the doors40 or by forced draft through the pipes 31, and fiows upwardly throughthe piers in cooling relation to the refractory blocks 29. This airescapes into the furnace through the channels 35, and because of theproximity of the air jets to the entering fuel stream they are of greatassistance in maintaining ignition of the fine fuel particles.Accordingly these particles burn in suspension, as desired, instead ofbeing carried out of the furnace is an unconsumed form by the furnacegases. The air cooling of the blocks 29 is so effective that they willremain in proper Operating condition throughout a. long life of usefulservice. The bars 33 serve to anchor the blocks firmly in their properpositions.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. A furnace comprising a grate, walls defining a combustion chamber andincluding a front wall with it lower edge spaced above the grate, thegrate being located within the combustion chamber, an upright pier ofrearwardly converging cross section dividing the space beneath the wallinto two openings through which fuel may be admitted to the urnace, thepier having a vertical passage therein and vertical rows of channelsleading laterally from the passage to the adjacent openings, and meansto circulate air through the passage and thence through the saidchannels 2. A furnace comprising a grate, walls defining a combustionchamber and including a front wall with its lower edge spaced above thegrate, the grate being located within the combustion chamber, twolaterally spaced upright piers beneath the said wall and forming thesides of a rearwardly and laterally flaring opening, a spreader stokermechanism arranged to project fuel rearwardly through the said openingto the grate, each pier having a vertical passage therein and a verticalrow of channels leading laterally from the passage to the said opening,and means to circulate air through the passage and thence through thesaid channels. i

3. A furnace comprising a grate, walls defining a combustion chamber andincluding a front wall with its lower edge spaced above the grate, thegrate being located within the combustion chamber, a series ofsuperimposed refractory blocks of rearwardly converging shape in planforming an upright pier dividing the space beneath the front wall intotwo openings, spreader stoker mechanisms arranged to project fuelrearwardly through the said openings to the grate, the blocks being ofhollow Construction to provide a, vertical passage within the pier andchannels leading laterally from the passage to the said openings, andmeans to supply air to the passage for discharge from the said channelsand mixture with the fuel particles traveling through the openings.

4. A furnace comprising a grate, walls defining a combustion chamber andincluding a front wall with its lower edge spaced above the grate, thegrate being located within the combustion chamber, an upright metalplate at the front of the furnace, a series of superimposed refractoryblocks forming an upright pier dividing the space beneath the wall intotwo openings through which fuel may. be admitted rearwardly into thefurnace, each block being of bifurcated shape in plan with the twobranches thereof engaging the rear surface of the said plate to providea vertical passage within the pier, and means to circulate air throughthe said passage.

5. A furnace comprising a grate, walls defining a combustion chamber andincluding a front wall with its lower edge spaced above the grate, thegrate being located within the combustion chamber, an upright metalplate at the front of the furnace, a series of superimposed refractoryblocks forming an upright pier dividing the space beneath the wall intotwo openings through which fuel may be admitted rearwardly into thefurnace, each block being of bifurcated shape in plan with the twobranches thereof engaging the rear surface of the said plate to providea, vertical passage within the pier, a vertical flanged metal barlocated within the passage and secured to the said late, lugs on theblocks engaging the bar to hold the blocks in position, and means tocirculate air through the said passage.

6. A furnace comprising a grate,`walls defining a combustion chamber andincluding a, front wall with its lower edge spaced above the grate, thegrate being located within the combustion chamber, an upright metalplate at the front of the furnace, a series of superimposed refractoryblocks forming an upright pier dividing the space beneath the wall intotwo openings through which fuel may be admitted rearwardly into thefurnace, each block being V -shaped in plan with the two branchesthereof engaging the rear surface of the said plate to provide avertical passage within the pier, the blocks having grooves thereinforming channels leading laterally from the said passage to the saidopenings, and means to circulate air through the passage and thencethrough the said channels.

GUSTAV A. REHM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,529, 83 Howren Mar. 10, 19251,693,400 Nygaard Nov. 27, 1928 896,440 DeBall Aug. 18, 1908 326,547Collis Sept. 22, 1885 47,049 Stewart Mar. 28, 1865 459,892 Weir Sept.22, 1891 613,'785 Sieben Nov. 8, 1898 1,789,223 Drake et al. Jan. 13,1931 1,360,250 Priebe Nov 23, 1920 1,604,648 Lundgren Oct. 26, 19261,944,948 v Preston 1 Jan. 30, 1934

